Cathodoluminescent display devices are well known in the art and commonly referred to as cathode ray tubes (CRTs). CRTs are commonly employed to provide visual information in systems such as television, radar, computer display, aircraft navigation and instrumentation. CRTs are commonly operated by scanning a very small cross-sectional beam of electrons horizontally and vertically with respect to a layer of cathodoluminescent material (phosphor) which is deposited on the back side of the viewing area of the CRT. By so doing a desired image will be produced on the viewing area as the incident electrons excite photon emission from the phosphor.
Since the very small cross-sectional area electron beam is scanned over the entire active area of the CRT it dwells on a particular spot for only a very short period of time. In the instance of CRTs utilized in commercial television applications the dwell time is on the order of a few tens of nano-seconds. In order to operate CRTs with reasonable brightness levels for viewing it is necessary that during the short dwell time as many photons as possible be generated from the phosphor. Accordingly, electron beams of high current density are commonly employed to energize the phosphor. This results in operation of the phosphor in a saturation mode wherein additional electron excitation provides diminishing photon generation. A number of shortcomings may be attributed to this mode of operation which include reduced phosphor lifetime (phosphor lifetime is an inverse function of deposited charge), phosphor heating, poor resolution, and poor overall efficiency. Phosphor heating results from the increase in energy which must be dissipated in the viewing screen (faceplate) of the CRT as a result of increased electron current. Poor resolution occurs due to beam spreading which results from the increased current density electron beam. Efficiency degrades as a result of operating in a saturation mode wherein few activation centers remain to accept a transfer of energy from the incoming energetic electrons.
Alternatives to the CRT have been proposed which include devices such as back-lit liquid crystal displays, plasma displays, electroluminescent displays, and flat field-emission displays. All of these alternative techniques fail to provide superior brightness characteristics and resolution which are deemed essential for evolving display products.
Accordingly, there exists a need for a device, technology, or method which overcomes at least some of the shortcomings of the prior art.